6,7‐Benzotropolone Syntheses Based on Ring‐Closing Metatheses and Four‐Electron Oxidations
作者:Michael Kreibich、Manuel Gemander、David Peter、Dharmendra B. Yadav、Charles B. de Koning、Manuel A. Fernandes、Ivan R. Green、Willem A. L. van Otterlo、Reinhard Brückner
DOI:10.1002/ejoc.202000256
日期:2020.5.22
Homoallyl ortho‐vinylaryl ketones were prepared through several different routes. In the presence of 1–2 mol‐% Grubbs‐II catalyst, these substrates cyclized to give 6,7‐dihydrobenzocyclohepten‐5‐ones. The enolates derived therefrom by treatment with NaHMDS in THF were oxidized by a stream of molecular oxygen at 0 °C. This furnished 6‐hydroxybenzocyclohepten‐5‐ones (“6,7‐benzotropolones”).
均烯丙基邻乙烯基芳基酮是通过几种不同的途径制备的。在1-2%摩尔%的Grubbs-II催化剂存在下,这些底物环化生成6,7-二氢苯并环庚烯-5。通过用NaHMDS在THF中处理而从中得到的烯醇化物在0℃下被分子氧流氧化。这提供了6-羟基苯并环庚酮-5(“ 6,7-苯并tropolones”)。